Service of corundum plates in sliding gates during teeming of steel into ingot molds from 140-ton ladles

How corundum refractories are wetted by molten steel

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Owing to the speeding up of metallurgical processes in recent years, a range of highstrength refractories has been developed and introduced in the iron and steel industry, including those based on sintered corundum.The stable high-temperature strength and high hardness mean they can be used for making constructions such as gate-valve tiles [2].However, in developing a method for making and introducing these tiles, together with the above properties, it is necessary to consider the degree of resistance of the material to the corrosive action of the metal jet. The depth of penetration of the molten metal into the refractory and the strength of bonding of the hardening metal film with the surface of the tile during its movement when the valve is opened determine the service life of the valve and, to a large extent, depend on the wetting of the refractory by the steel.

This article describes the results of studying the wetting by steel of refractory corundum materials used by industry and which might be useful for making gate valve tiles [3,4].

The wettability was determined with steel 45 (GOST 1050-60).

Specimen-supports measuring 14 x ii x 2 mm were cut from tiles prepared at the experimental factory of the All-Union Institute of Refractories (VIO), using a technology based on the use of sintered corundum as the filler (fractions 2-0 ram) and finely milled constituent (fractions minus 0.063 mm); the corundum was obtained by calcining alumina with different sintering additives.

These consisted of infusible oxides (MgO, CraOa, ZrO=) and silicon-containing materials (kaolin, silicon polymers).

The corundum refractories containing addition of silicone polymers were developed by VIO together with the Institute of Silicate Chemistry, Academy of Sciences of the USSR.

The proportion of additives and mixtures of them was from 1 to 10% by weight.

The open porosity of the tiles studied came within comparable limits and equaled 9-12%.

The wetting angle 0 of the substratum was determined by the sessile bubble method on VIO equipment [5] at 1550~ in pure argon.

The surface tension of the steel OL_ G was calculated from the Bashforth and Adams tables [6].

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Wear on periclase and corundum tiles in sliding steel casting gates

“…The high cost and the stringent specifications for the tiles for steel-casting gates has made it necessary to study the wear on these gates in some depth. This problem has already been considered in a few publications [1][2][3][4].The wear on the tiles in the sliding steel-casting gates was determined after the co~monest grades of steel had been cast on MNLZ and in molds. The state of the tiles after casting was evaluated by visual inspection of the dismantled gate.…”